TY - JOUR
T1 - Is essential tremor symmetric? Observational data from a community- based study of essential tremor
AU - Louis, Elan D.
AU - Wendt, Kristin J.
AU - Pullman, Seth L.
AU - Ford, Blair
N1 - Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 1998/12
Y1 - 1998/12
N2 - Background: Essential tremor (ET) has been variably portrayed in the literature both as a symmetric arm tremor and as an asymmetric arm tremor. Few quantitative clinical or neurophysiological data specifically address the issue of tremor asymmetry in ET. Objectives: To examine a community-dwelling cohort of subjects with ET to (1) estimate the prevalence of tremor asymmetry and (2) quantify the magnitude of tremor asymmetry. Methods: Fifty-four subjects with ET, identified in a community-based study of ET in New York City, underwent a Tremor Interview and a videotaped Tremor Examination. The examination included 6 tasks: sustained arm extension, pouring water, drinking water, using a spoon, finger-to-nose movements, and drawing spirals with each arm. Two neurologists rated the severity of tremor using a 0 to 3 clinical rating scale and a total tremor score was calculated (range, 0-36). Fourteen (25%) of 54 subjects also underwent quantitative computerized tremor analysis. Results: The prevalence of asymmetry depended on the definition of asymmetry, small to moderate differences between sides were common. The mean side-to-side difference in clinical ratings for each of the 6 tasks was 0 54 of 3 points, which represented a 1 32-fold difference between sides. Clinical rating scores were higher in the nondominant arm in 39 subjects (72%), higher in the dominant arm in 9 (17%), and equal in 6 (11%). The 2 left-handed subjects had higher clinical ratings on the right. During quantitative computerized tremor analysis, there was a 1.71-fold mean difference between tremor amplitudes in the dominant and nondominant sides, and in 12 subjects (86%), the maximum tremor amplitude was in the nondominant arm. Conclusions: Small to moderate differences between sides were common in ET. In most community-dwelling subjects, tremor amplitude was greatest in the nondominant arm. In contrast, clinic-based studies have reported greater tremor in the dominant arm, those with ET who seek medical attention are more likely to exhibit severe tremor in their dominant arms. This study documents that mild asymmetry is a fundamental property of ET and that tremor is more severe in the nondominant arm.
AB - Background: Essential tremor (ET) has been variably portrayed in the literature both as a symmetric arm tremor and as an asymmetric arm tremor. Few quantitative clinical or neurophysiological data specifically address the issue of tremor asymmetry in ET. Objectives: To examine a community-dwelling cohort of subjects with ET to (1) estimate the prevalence of tremor asymmetry and (2) quantify the magnitude of tremor asymmetry. Methods: Fifty-four subjects with ET, identified in a community-based study of ET in New York City, underwent a Tremor Interview and a videotaped Tremor Examination. The examination included 6 tasks: sustained arm extension, pouring water, drinking water, using a spoon, finger-to-nose movements, and drawing spirals with each arm. Two neurologists rated the severity of tremor using a 0 to 3 clinical rating scale and a total tremor score was calculated (range, 0-36). Fourteen (25%) of 54 subjects also underwent quantitative computerized tremor analysis. Results: The prevalence of asymmetry depended on the definition of asymmetry, small to moderate differences between sides were common. The mean side-to-side difference in clinical ratings for each of the 6 tasks was 0 54 of 3 points, which represented a 1 32-fold difference between sides. Clinical rating scores were higher in the nondominant arm in 39 subjects (72%), higher in the dominant arm in 9 (17%), and equal in 6 (11%). The 2 left-handed subjects had higher clinical ratings on the right. During quantitative computerized tremor analysis, there was a 1.71-fold mean difference between tremor amplitudes in the dominant and nondominant sides, and in 12 subjects (86%), the maximum tremor amplitude was in the nondominant arm. Conclusions: Small to moderate differences between sides were common in ET. In most community-dwelling subjects, tremor amplitude was greatest in the nondominant arm. In contrast, clinic-based studies have reported greater tremor in the dominant arm, those with ET who seek medical attention are more likely to exhibit severe tremor in their dominant arms. This study documents that mild asymmetry is a fundamental property of ET and that tremor is more severe in the nondominant arm.
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U2 - 10.1001/archneur.55.12.1553
DO - 10.1001/archneur.55.12.1553
M3 - Article
C2 - 9865800
AN - SCOPUS:0031700559
SN - 0003-9942
VL - 55
SP - 1553
EP - 1559
JO - Archives of neurology
JF - Archives of neurology
IS - 12
ER -